With the advent of stereophonic sound, various techniques were developed to convert or `re-process` existing monophonic programs for stereophonic broadcast or recording systems. These included modifying the equalization phase or tonal qualities of separate copies of the monophonic program for the left and right channels. While true stereophonic or binaural effects may not have been achieved, the effects were much improved over feeding the identical monophonic signal to both channels.
Similarly, with the almost universal use of color production, exhibition and broadcast systems for motion pictures and television, systems have been developed to convert existing monochrome or black and white materials to color programs. Such a systems is described in applicant Geshwind's Pat. No. 4,606,625, issued Aug. 19, 1986. The results of these colorized products, while not always identical to true color motion pictures, are more suitable than black and white for color systems.
There have been a number of systems for exhibition or display of left- and right-eye pairs of binocular motion pictures. Early systems required two completely redundant projection or display systems; e.g. two film projectors or CRT television displays, each routed to one eye via mirrors. Other systems require either complicated and expensive projection or display systems, or expensive `glasses` to deliver two separate images. For example:
red- and green-tinted monochrome images are both projected or displayed to be viewed through glasses with left and right lenses tinted either red or green; PA1 two full-color images are projected through mutually perpendicular polarized filters and viewed through glasses with lenses that are also polarized in the same manner; PA1 left and right images are displayed on alternate odd and even fields (or frames) of a standard (or high scan rate) television CRT and are viewed through `glasses` with shutters (either rotating blades or flickering LCDs, for example) that alternate the view of left and right eyes in synchrony with the odd or even fields of the CRT.
Of the above systems, the second is not at all usable with standard home television receivers, the third requires very expensive `glasses` and may flicker with standard home receivers, and the first produces only strangely tinted monochrome images. Further, none of the systems may be broadcast over standard television for unimpeded viewing without special glasses.
Thus, until now, compatible (i.e., viewable as two-dimensional, without glasses) home reception of b 3-D images was not possible. However, a new system, which takes advantage of differential processing of left- and right-eye images in the human perceptual system, delivers a composite image on a standard home television receiver that can be viewed as a normal 2-D picture without glasses. Very inexpensive glasses, with one light and one dark lens, accentuate the differential processing of the image, as viewed by each eye, to produce a 3-D depth effect.
Practical, inexpensive, compatible (with standard TV) 3-D television may now become widespread. In addition to materials specifically produced for the new system (or other 3-D systems) conversion of standard 2-D programs to 3-D format would provide additional product to broadcast using the new compatible system (or for other 3-D projection systems).